Pneumatic Actuators vs Hydraulic. Let it Give a Little.

As I’ve mentioned previously, and as you likely thought of when you were 10 years old (I didnt, but I wasnt the smartest calf in the heard), most mechanical means of movement arent forgiving. Hydraulics, motors, whatever other actuators you use, if anything is in their path between their current position and their programmed destination, it will attempt to keep on pushing through, and if they are strong enough, will not give to a reasonable degree. In most industrial or commercial cases, this is fine. We dont want hydraulic rams on excavators giving when it hits a patch of hard packed ground. You want that beast to bust on through without a grunt. However when you want a gripper on your Mech to pick up an apple without making apple sauce, some more finesse is necessary. Sometimes you need only a little finesse. Sometimes you need a lot. Like with baby chicks. Dont hurt the baby chicks with your heartless cold robot-hands.

Anyway, air is squishy and compresses nicely for a situation like this. So a pneumatic ram, when pressed against an obstacle, will need to increase pressure to compensate for the compression of the air inside. Of course this also happens with hydraulics, but it compresses so little you have less room to work with. Of course you can have pressure sensors on the tips of hydraulics too to sense the give or pressure between your Mech’s robot fingers and the object of its pressure, but lets keep it simple and not risk the abrupt demise of your grips focus. Using air will give you a nice buffer to sense the increase in pressure in your air reservoir, and stop/adjust/keep-pressing/whatever.  The smaller your air reservoir, the less tolerance though, so this would be adjustable by your setup.

You could even have a hybrid approach, where an air bladder of some sort is within a hydraulic system to give a little of airs natural give, but then the brute force of hydraulics immediately behind

 

Here is a great video demonstrating the give of air in a pneumatic cylinder (And the article in which I found it, from Make!)

 

Rehab Exoskeleton – HARMONY, by ReNeu Robotics Lab

Model: HARMONY

Company/Organization: Rehabilitation and Neuromuscular (ReNeu) Robotics Lab, Cockrell School of Engineering at The University of Texas at Austin

Maker/Developer: Dr. Ashish Deshpande & a team of grad students form the Rehabilitation and Neuromuscular (ReNeu) Robotics Lab.

Purpose: Bilateral upper back/shoulders/arm therapy. Primary focus is for stroke and spinal cord injury patients.

Power Source: External source

Price: n/a

Actuator: unknown type x 14

Joints: Scapulae, shoulders, elbows, wrists

Overview: Therapy exoskeletons for arm and shoulder movements are typically designed for use on one side of the body at a time. However, HARMONY is designed to be used for bilateral therapy needs, allowing articulation via 14 actuators with joints in the upper-back (scapulae), shoulders, elbows, and wrist.  HARMONY is adjustable for various body sizes, and connects at three different places on each side of the body: two straps on the upper arms, and a bar for each hand to grip.

Special focus was put on ensuring the shoulder motions of HARMONY closely mimicked that of the natural human shoulder movements and range of motion. You can see in the below image, when the patient shrugs hsi shoulders (Right) the shoulder mechanism of HARMONY moves up with him.

HARMONY is designed to feel weightless to the user, but that is a fully adjustable setting based on the individual’s needs. It can provide more or less resistance, and correct a user’s movements if they deviate off a prescribed range of motion.

HARMONY therapy exoskeleton by ReNeu Robotics Lab - Elbow and wrist closeup
HARMONY therapy exoskeleton by ReNeu Robotics Lab – Elbow and wrist closeup

 

Computer software is used with HARMONY, taking sensor measurements up to 2000 times per second. This data is used by therapists to monitor and plan a patients progress and ongoing therapy.

 

Watch the video below, from the Cockrell School of Engineering at UT Austin for a quick demonstration and overview.

 

Related Publications by ReNeu Robotics Lab

 

 

HARMONY rehab Exoskeleton – More articles and releases

ReNeu Robotics Lab – Related research

 

More on Dr Ashish Deshpande

Dr Ashish D. Deshpande
Dr Ashish D. Deshpande

Manual Control Exoskeleton Legs for Paraplegics

The good smart folks at École Polytechnique Fédérale de Lausanne have developed a nice “simple” set of legs to help folks with lower limb difficulties. However, I only say “simple” because there is no crazy complex or invasive interface with nerves, thoughts, or carefully controlled passings of gas (I’ll see if I can get that last one to market).  The in put on this unit is a basic manually triggered command for each step using hand controls. As the article and video say, they will improve it eventually to a point where its just a “Walk” command and the legs will manage the steps for you.

 

 

When it comes to building Mechs, there are two primary types that come to mind. A robotic suite that you wear, like Iron Man, or more of a vehicle that you drive, like MechWarrior. In the latter case, this technology would directly apply. More specifically, the level they will eventually develop it to, where you say walk (well, not verbally. Through some other input means. Maybe even a simple joystick), and it will walk forward. The machine will handle all the nitty gritty of leg motion and foot placement.  A Mech developer could always go the route of wearing some sort of controlling suit within the cockpit (or wherever) within the Mech,and have those movements directly translated to the Mechs own legs, but I wonder how effective that would be. Who knows, we arent quite there yet, but its coming! Get ready!

 

Mech hand control, and feedback

Back in 2014, a company called Dexta Robotics launched a Kickstarter campaign to fund development of their “VR Exoskeleton glove” called the Dexmo (Article on it from roadtovr.com). Its a big ungainly looking thing, and I can easily envision a users hands bumping into each other through normal use, but the core function is great. It gives resistive feedback to your own hands, reflecting what you are virtually touching if using it with a VR headset. Alternatively, with some adaption, it could reflect what your Mech is physically touching. To avoid smashing all things you grasp with your Mech’s cold dead metal hands, this is critical for any Mech that will touch objects more sensitive that rocks and solid steel. As I alluded to, this glove is not designed specifically for Mech or robot control (at least not that I’ve seen so far), but its function is ultimately what is needed to safely handle objects while operating a Mech. Certainly, sensors will be needed in the hands/grippers of a Mech, but that is the case for any feedback system. The glove is the other half of that equation, applying that sensory data directly to your own flesh.

Unfortunately, the Kickstart campaign failed. However, all is not lost! It appears the team has persevered and maybe will have a product for sale soon? Or maybe they’re looking for a larger company to buy them for their device and its associated intellectual property. I cant really tell from the website, but it has some interesting information on it.

Check out the video below, and for more info, head to their website: http://www.dextarobotics.com

 

 

Step one towards making the bionic woman(or man) a reality

Motherboard has a great article and video about a prosthetic that can be controlled by the users thought. However, that is not where the awesome stops. This system actually gives the user an actual sense of touch through the prosthetic.

This is amazing stuff. In the user’s case, it did require remapping of some nerves, so this would be an invasive implementation for the average person. Regardless, this sort of 2 way communication between us and a mechanical device is a critical component towards intuitive Mechs/exoskeletons/robotic suits/etc. With such augmented strength, (even with our own natural strength) sensory feedback is crucial to avoid damaging items we touch, and to avoid damaging ourselves, or that of our mechanical appendages. If you are in a Mech suit, say rescuing people form a disaster area, a car crash, anything… you cannot grab a living victim without the risk of causing them more harm if you don’t have the ability to sense how much pressure you are placing on them.

I don’t propose we have Mech users/pilots/wearers remove limbs and have nerves rerouted to facilitate this need. This is version 1, and it is not applicable for most. However, the technology will advance and become more adaptable for others, without such extreme measures to implement it.

With that said, its amazing, its a major stepping stone, and I’m excited for the users to regain some of their lost abilities!

 

Watch the video below, & check out Motherboard’s full article on it here!

 

 

The Power Loader from Aliens, in Meat Space!

The Caterpillar P-5000 Powered Work Loader (AKA, Power Loader), from the classic film, Aliens , was an impressive little Mech built for the simple of purpose of being a fancy pants forklift with legs. It has no life support, weapons, jets, HUD, or pasta-maker attachments (at least none that I saw). However, it handily out-fight the alien Queen in this epic fight scene (Warning, a touch of cursing in this video).

Now with that said a Japanese company has developed (or rather, is developing) a similar Mech, or something close to it. Below is a video they posted on YouTube which goes over its basics. If we can paint it yellow,  get Sigourney Weaver to strap it on, and toss a Xenomorph into the mix, we’ll have a real life recreation of that fight scene!